leaves have left

This is an interesting image but there is a lot of noise.  The details show it to be shot at ISO 200 which makes me suspect that the cause of the noise must be from post processing.  Too much sharpening maybe?

I'm also confused why it was shot at F5.  The shutter speed is unclear since it shows something like 100/25999.

You may also want to research the lens that you used and find out where its sweet spot is.  The chromatic aberration that's plainly visible tells me that you're asking more from this camera/lens combo than it can provide at F5.

I would be willing to bet that at F8 or F11 you'll get much sharper results and with a stationary subject like this you could use a tripod and shoot whatever shutter speed is necessary to get the exposure correct.

You have a good eye but you may need to either upgrade your equipment or learn how to squeeze every last drop of performance out of what you have.

Cal, I can't comment to much on the technical end of things. Subject wise, I absolutely love it. I did notice what Mark commented on.  I also wish that you could of angled it or gotten close enough to cut out the little tree on the right. However, it looks like maybe you had obstacles that prevented you from getting physically closer. The subject, colors, and atmosphere of this are wonderful.